Surgical management of lumbar degenerative spinal stenosis with spondylolisthesis via posterior reduction with minimal laminectomy

Does loss of spondylolisthesis reduction impact clinical and radiographic outcomes after minimally invasive transforaminal lumbar interbody fusion?

BACKGROUND CONTEXT

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a common operative approach to address degenerative lumbar stenosis and spondylolisthesis which has failed nonoperative care. Compared to open TLIF, MI-TLIF relies to a greater extent on indirect decompression resulting in a heightened awareness of spondylolisthesis reduction among MI surgeons. To what extent intraoperative reduction is achieved as well as the rate and clinical impact of loss or reduction and slip recurrence remain unknown.

PURPOSE

To determine the rate and clinical impact of slip recurrence after MI-TLIF with expandable cage technology STUDY DESIGN/SETTING: Retrospective Cohort Study PATIENT SAMPLE: Patients undergoing MI-TLIF for degenerative spondylolisthesis using an articulating, expandable cage OUTCOME MEASURES: Patient-reported outcome measures (PROMs), including the Oswestry Disability Index (ODI), visual analog scale (VAS) for back/leg pain, Short Form-12 (SF-12), and PROMIS Physical Function (PF) METHODS: Patients undergoing MI-TLIF for degenerative spondylolisthesis using articulating, expandable cages from 2017 to 2019 were retrospectively studied. Lateral radiographs were reviewed and evaluated for the presence or absence of spondylolisthesis preoperatively, intraoperatively, and at follow-up times including 2 weeks, 6 weeks, 12 weeks, 6 months, and 1 year postoperatively. Spondylolisthesis was measured from the posterior inferior corner of the cephalad vertebra to the posterior superior corner of the caudal vertebra, with any measurement >1 mm classified as spondylolisthesis, and Meyerding grade was noted. Intraoperative reduction was measured, and loss of reduction was defined as >1 mm increase in spondylolisthesis comparing follow-up imaging to intraoperative films. PROMs were recorded at the preoperative and follow-up time points. Fusion was assessed at 1 year postoperatively via CT.

RESULTS

A total of 63 patients and 70 levels were included, with mean age 59.8 years (SD,13.8). 19 levels (27.1%) had complete reduction intraoperatively, 40 (57.1%) had partial reduction, and 11 (15.7%) had no reduction. Of the 30 levels with loss of reduction (50.8%), 20 (66.7%) occurred by 2 weeks postoperatively and 28 (93.3%) occurred by 12 weeks postoperatively. At 6 months, there were significant differences between those who had loss of reduction and those who did not in VAS back pain (3.0 vs. 0.9, p = .017) and SF-12 PCS (41.5 vs. 50.0, p = .035), but no differences were found between the groups for any instruments at any other time points. The overall fusion rate was 82.1% (32/39) at 1 year postoperatively. There was no significant difference in fusion rate between the loss of reduction (16/20) and no loss of reduction (20/23) groups. Patients with loss of reduction had no difference in reoperation rate (1/28) compared to those without loss of reduction (2/24).

CONCLUSIONS

While a majority of patients demonstrated reduction intraoperatively, 51% had loss of reduction, most commonly in the acute postoperative period. There were few differences in PROMs between patients who had loss of reduction and those who did not, suggesting that radiographic loss of reduction after MI-TLIF in the setting of degenerative spondylolisthesis may not be clinically meaningful.

Biomechanical evaluation of traditional posterior versus anterior spondylolisthesis reduction in a cadaveric grade I slip model

OBJECTIVE

Posterior reduction with pedicle screws is often used for stabilization of unstable spondylolisthesis to directly reduce misalignment or protect against micromotion while fusion of the affected level occurs. Optimal treatment of spondylolisthesis combines consistent reduction with a reduced risk of construct failure. The authors compared the reduction achieved with a novel anterior integrated spacer with a built-in reduction mechanism (ISR) to the reduction achieved with pedicle screws alone, or in combination with an anterior lumbar interbody fusion (ALIF) spacer, in a cadaveric grade I spondylolisthesis model.

METHODS

Grade I slip was modeled in 6 cadaveric L5-S1 segments by creation of a partial nucleotomy and facetectomy and application of dynamic cyclic loading. Following the creation of spondylolisthesis, reduction was performed under increasing axial loads, simulating muscle trunk forces between 50 and 157.5 lbs, in the following order: bilateral pedicle screws (BPS), BPS with an anterior spacer (BPS+S), and ISR. Percent reduction and reduction failure load-the axial load at which successful reduction (≥ 50% correction) was not achieved-were recorded along with the failure mechanism. Corrections were evaluated using lateral fluoroscopic images.

RESULTS

The average loads at which BPS and BPS+S failed were 92.5 ± 6.1 and 94.2 ± 13.9 lbs, respectively. The ISR construct failed at a statistically higher load of 140.0 ± 27.1 lbs. Reduction at the largest axial load (157.5 lbs) by the ISR device was tested in 67% (4 of 6) of the specimens, was successful in 33% (2 of 6), and achieved 68.3 ± 37.4% of the available reduction. For the BPS and BPS+S constructs, the largest axial load was 105.0 lbs, with average reductions of 21.3 ± 0.0% (1 of 6) and 32.4 ± 5.7% (3 of 6) respectively.

CONCLUSIONS

While both posterior and anterior reduction devices maintained reduction under gravimetric loading, the reduction capacity of the novel anterior ISR device was more effective at greater loads than traditional pedicle screw techniques. Full correction was achieved with pedicle screws, with or without ALIF, but under significantly lower axial loads. The anterior ISR may prove useful when higher reduction forces are required; however, additional clinical studies will be needed to evaluate the effectiveness of anterior devices with built-in reduction mechanisms.

Treatment for Degenerative Lumbar Spondylolisthesis: Current Concepts and New Evidence

PURPOSE OF REVIEW

Current guidelines for the optimal treatment degenerative spondylolisthesis are weak and based on limited high-quality evidence.

RECENT FINDINGS

There is some moderate evidence that decompression alone may be a feasible treatment with lower surgical morbidity and similar outcomes to fusion when performed in a select population with a low-grade slip. Similarly, addition of interbody fusion may be best suited to a subset of patients with high-grade degenerative spondylolisthesis, although this remains controversial. Minimally invasive techniques are increasingly being utilized for both decompression and fusion surgeries with more and more studies showing similar outcomes and lower postoperative morbidity for patients. This will likely be an area of continued intense research. Finally, the role of spondylolisthesis reduction will likely be determined as further investigation into optimal sagittal balance and spinopelvic parameters is conducted. Future identification of ideal thresholds for sagittal vertical axis and slip angle that will prevent progression and reoperation will play an important role in surgical treatment planning. Current evidence supports surgical treatment of degenerative spondylolisthesis. While posterolateral spinal fusion remains the treatment of choice, the use of interbodies and decompressions without fusion may be efficacious in certain populations. However, additional high-quality evidence is needed, especially in newer areas of practice such as minimally invasive techniques and sagittal balance correction.

Analysis of Recombinant Human Bone Morphogenetic Protein-2 Use in the Treatment of Lumbar Degenerative Spondylolisthesis

Study Design Retrospective database review. Objective To identify trends of the recombinant human bone morphogenetic protein-2 (rhBMP-2) use in the treatment of lumbar degenerative spondylolisthesis (LDS). Methods PearlDiver Patient Record Database was used to identify patients who underwent lumbar fusion for LDS between 2005 and 2011. The distribution of bone morphogenetic protein use rate (BR) in various surgical procedures was recorded. Patient numbers, reoperation numbers, BR, and per year BR (PYBR) were stratified by geographic region, gender, and age. Results There were 11,335 fusion surgeries, with 3,461 cases using rhBMP-2. Even though PYRB increased between 2005 and 2008, there was a significant decrease in 2010 for each procedure: 404 (34.5%) for posterior interbody fusion, 1,282 (34.3%) for posterolateral plus posterior interbody fusion (PLPIF), 1,477 (29.2%) for posterolateral fusion, and 335 (22.4%) for anterior lumbar interbody fusion. In patients using rhBMP-2, the reoperation rate was significantly lower than in patients not using rhBMP-2 (0.69% versus 1.07%, p < 0.0001). Male patients had higher PYBR compared with female patients in 2008 and 2009 (p < 0.05). The West region and PLPIF had the highest BR and PYBR. Conclusions Our data shows that the revision rates were significantly lower in patients treated with rhBMP-2 compared with patients not treated with rhBMP-2. Furthermore, rhBMP-2 use in LDS varied by year, region, gender, and type of fusion technique. In the West region, the posterior approach and patients 65 to 69 years of age had the highest rate of rhBMP-2 use.

Replacement of Vertebral Lamina (Laminoplasty) in Surgery for Lumbar Isthmic Spondylolisthesis: 5-Year Follow-Up Results

Study Design

A review of clinical and radiological outcomes of lumbar laminoplasty (LL) for the treatment of isthmic spondylolisthesis (ISL).

Purpose

The single session performance of posterior lumbar interbody fusion with allograft in the anterior column and providing the realignment of the vertebrae was presented as a preliminary report earlier.

Overview of Literature

Long-term surgical outcome of cervical laminoplasty in patients has been reported. But, outcome of LL in patients is unclear.

Methods

The long-term (5 years) year follow-up results of the LL technique are reported in this retrospective study. All patients underwent preoperative and postoperative direct X-ray, computed tomography, and magnetic resonance imaging. The patients that did not respond to conservative treatment were operated. Twenty-one (52.5%) female and 19 (47.5%) male patients were included.

Results

Mean age was 43,5 years (ranges, 22–57 years). The most common symptoms were low back pain (89%), pelvic and leg pain (69%) and reduction in walking distance (65%). A total of 180 pedicle screws were inserted in 40 patients; posterior lumbar interbody fusion and laminoplasty with reduction was performed in 20 patients for L4–L5, 12 patients for L5–S1, 4 patients for L3–L4–L5 and 4 patients for L4–L5-S1. Ten (25%) patients with ILL had accompanying spinal stenosis. The difference between preoperative and postoperative sagittal plane rotation and dislocation degrees and disc space heights were statistically significant in all patients (p<0.05). Solid grade 4 fusion was observed in 38 patients; in only 2 patients grade 2 pseudoarthrosis developed (5%), but these patients were asymptomatic. Visual analog scale, Prolo economical and functional scale was examined with an average follow-up 5.5 years.

Conclusions

LL technique has the advantages of shorter duration of operation, lack of graft donor site complications, protection of posterior column osseoligamentous structures and achievement of high fusion rates in one session.

Guideline summary review: An evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spondylolisthesis

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence-Based Clinical Guideline for the Diagnosis and Treatment of Degenerative Lumbar Spondylolisthesis features evidence-based recommendations for diagnosing and treating degenerative lumbar spondylolisthesis. The guideline updates the 2008 guideline on this topic and is intended to reflect contemporary treatment concepts for symptomatic degenerative lumbar spondylolisthesis as reflected in the highest quality clinical literature available on this subject as of May 2013. The NASS guideline on this topic is the only guideline on degenerative lumbar spondylolisthesis included in the Agency for Healthcare Research and Quality's National Guideline Clearinghouse (NGC).

PURPOSE

The purpose of this guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for patients with degenerative lumbar spondylolisthesis. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

A systematic review of clinical studies relevant to degenerative spondylolisthesis was carried out.

METHODS

This NASS spondyolisthesis guideline is the product of the Degenerative Lumbar Spondylolisthesis Work Group of NASS' Evidence-Based Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members used the NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guidelines were submitted to an internal peer review process and ultimately approved by the NASS Board of Directors. Upon publication, the Degenerative Lumbar Spondylolisthesis guideline was accepted into the NGC and will be updated approximately every 5 years.

RESULTS

Twenty-seven clinical questions were addressed in this guideline update, including 15 clinical questions from the original guideline and 12 new clinical questions. The respective recommendations were graded by strength of the supporting literature, which was stratified by levels of evidence. Twenty-one new or updated recommendations or consensus statements were issued and 13 recommendations or consensus statements were maintained from the original guideline.

CONCLUSIONS

The clinical guideline was created using the techniques of evidence-based medicine and best available evidence to aid practitioners in the care of patients with degenerative lumbar spondylolisthesis. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flow chart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/Pages/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx and will remain updated on a timely schedule.

Intraoperative reduction does not result in better outcomes in low-grade lumbar spondylolisthesis with neurogenic symptoms after minimally invasive transforaminal lumbar interbody fusion-a 5-year follow-up study

BACKGROUND CONTEXT

Intraoperative reduction of low-grade lumbar spondylolisthesis (LGLS) remains disputed. There is currently no published data comparing midterm outcomes of reduction versus in situ fusion.

PURPOSE

This study aimed to compare mid-term clinical, radiological, and perioperative outcomes for reduction versus in situ fusion in LGLS with neurogenic symptoms.

STUDY DESIGN/SETTING

A retrospective review of prospectively collected spine registry data in a single institution was carried out.

PATIENT SAMPLE

All patients who underwent minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) for LGLS with neurogenic symptoms with a minimum 5-year follow-up comprised the patient sample.

OUTCOME MEASURES

Self-reported measures were Oswestry Disability Index, North American Spine Society Neurogenic Symptom Score, Health Outcomes Survey Short Form-36 score, and Numerical Pain Rating Scale (back and leg pain). Radiological outcomes were fusion grading, adjacent segment degeneration (ASD), and implant failure or loosening. Perioperative outcomes were fluoroscopic time, operative time, intraoperative blood loss, opioid analgesia usage, time to ambulation, duration of hospitalization, and complication rate. Functional outcomes were patient satisfaction rate and rate of return to full function.

METHODS

A retrospective review was performed on prospectively collected registry data of patients undergoing MIS TLIF for LGLS with neurogenic symptoms, from 2004 to 2009. The operative technique and postoperative protocol were standardized. Two groups were formed based on complete reduction of the spondylolisthesis (reduction group [RG]) or the lack thereof (non-reduction group [NRG]) in the immediate postoperative radiograph. Outcomes at baseline, 6 months, 2 years, and 5 years postsurgery were compared.

RESULTS

There were 56 patients included (RG=30, NRG=26). The two groups had comparable baseline characteristics: demographics, body mass index, spondylolisthesis etiology, spinal level involved, bone graft and bone morphogenetic protein used, and all self-reported outcome measures. Perioperative outcomes were not significantly different. The early complication rate (RG=3.3%, NRG=19.2%, p=.086) and late complication rate (RG=10%, NRG=23.1%, p=.184) were similar. All patients achieved Bridwell grade 1 fusion from 2 years onward. Adjacent segment degeneration rate at 5 years was similar (RG=10%, NRG=0%, p=NS). Both groups showed significant postoperative improvement in all self-reported measures with no significant differences between the two groups at all follow-up points. Functional outcomes were equivalent.

CONCLUSIONS

Intraoperative reduction does not improve outcomes in LGLS with neurogenic symptoms after MIS TLIF. Adequate decompression and solid fusion are likely the keys to good mid-term outcomes.

Surgical Outcome of Reduction and Instrumented Fusion in Lumbar Degenerative Spondylolisthesis

BACKGROUND

Lumbar degenerative spondylolisthesis (LDS) is a degenerative slippage of the lumbar vertebrae. We aimed to evaluate the surgical outcome of degenerative spondylolisthesis with neural decompression, pedicular screw fixation, reduction, and posterolateral fusion.

METHODS

This before-after study was carried out on 45 patients (37 female and 8 male) with LDS operated from August 2008 to January 2011. The patients' pain and disability were assessed by visual analogue scale (VAS) and Oswestry disability index (ODI) questionnaire. In surgery, we applied distraction force to facilitate slip reduction. All the intra- and postoperative complications were recorded. The paired t-test and Pearson correlation coefficient were used for statistical analysis.

RESULTS

The mean age of patients and mean follow-up period were 58.3±3.5 years and 31.2±4.8 months, respectively. The mean slip correction rate was 52.2% with a mean correction loss of 4.8%. Preoperative VAS and ODI improved from 8.8 and 71.6 to postoperative 2.1 and 28.7, respectively. Clinical improvement was more prominent in more reduced patients, but Pearson coefficient could not find a significant correlation.

CONCLUSION

Although spinal decompression with fusion and posterior instrumentation in surgical treatment of the patients with LDS result in satisfactory outcome, vertebral reduction cannot significantly enhance the clinical improvement.

Lever reduction using polyaxial screw and rod fixation system for the treatment of degenerative lumbar spondylolisthesis with spinal stenosis: technique and clinical outcome

Background

The management for degenerative lumbar spondylolisthesis with spinal stenosis remains controversial. Reduction of lumbar spondylolisthesis has been performed via numerous techniques. Most of them need extra reduction assembly.

Methods

In this retrospective analysis, 27 patients of degenerative lumbar spondylolisthesis with spinal stenosis underwent reduction using polyaxial screw and rod constructs and posterolateral fusion. The average age at the time of surgery was 53 ± 3.23 years. The outcome measures consisted of a radiographic assessment of deformity and fusion rate and a clinical assessment of perioperative improvement in low back pain and function. Preoperative and postoperative radiographic evaluation included the percent slip, slip angle, and the lumbar lordosis between L1 and the sacrum measured using the Cobb method. Before surgery and at the final follow-up, the Oswestry Disability Index (ODI) and the visual pain analog scale (VPAS) between 0 (no pain) and 10 (maximal pain) were quantified.

Results

The average follow-up period more than 5 years was available. The mean operative time was 90.19 ± 14.51 min, and the mean blood loss during surgery was 152.59 ± 45.71 ml. The mean length of incision was 4.83 ± 0.63 cm. The average percent slippage and the mean slip angle were, respectively, 19.8 ± 4.49% and 9.69 ± 3.79° before surgery, 5.09 ± 3.40% and 6.39 ± 3.16° after surgery, and 5.67 ± 3.92% and 7.21 ± 3.05° at the last follow-up. The average lumbar lordosis was 36.88 ± 2.64° before surgery, 41.96 ± 1.64° after surgery, and 40.27 ± 1.19° at the final follow-up. No neurologic deficit occurred. Solid fusion was achieved for all cases. Compared with the outcome preoperation, the data improved from 6.56 ± 1.40 to 2.48 ± 1.16 for VPAS pain scores and from 32.22 ± 3.57 to 10.93 ± 4.93 for the ODI at the final follow-up.

Conclusions

Lever slip reduction maneuver techniques using polyaxial screw and rod fixation system was simple and practicable. The treatment outcomes showed satisfactory radiographic characteristics and clinical results. The length of the incision was relatively small with a low intraoperative blood loss and short operation time.

Pedicle-Screw-Based Dynamic Systems and Degenerative Lumbar Diseases: Biomechanical and Clinical Experiences of Dynamic Fusion with Isobar TTL

Dynamic systems in the lumbar spine are believed to reduce main fusion drawbacks such as pseudarthrosis, bone rarefaction, and mechanical failure. Compared to fusion achieved with rigid constructs, biomechanical studies underlined some advantages of dynamic instrumentation including increased load sharing between the instrumentation and interbody bone graft and stresses reduction at bone-to-screw interface. These advantages may result in increased fusion rates, limitation of bone rarefaction, and reduction of mechanical complications with the ultimate objective to reduce reoperations rates. However published clinical evidence for dynamic systems remains limited. In addition to providing biomechanical evaluation of a pedicle-screw-based dynamic system, the present study offers a long-term (average 10.2 years) insight view of the clinical outcomes of 18 patients treated by fusion with dynamic systems for degenerative lumbar spine diseases. The findings outline significant and stable symptoms relief, absence of implant-related complications, no revision surgery, and few adjacent segment degenerative changes. In spite of sample limitations, this is the first long-term report of outcomes of dynamic fusion that opens an interesting perspective for clinical outcomes of dynamic systems that need to be explored at larger scale.

Avaliação dos pacientes submetidos à descompressão e artrodese póstero-lateral devido à espondilolistese degenerativa com dois anos de acompanhamento

OBJETIVO: Avaliar os resultados da descompressão e da artrodese póstero-lateral na espondilolistese degenerativa em pacientes que têm como sintoma principal a claudicação neurogênica. MÉTODO: Foram selecionados 21 pacientes com espondilolistese degenerativa, com indicação de tratamento cirúrgico. Foram avaliados 8 homens e 13 mulheres com idades entre 36 e 77 anos. O procedimento cirúrgico padronizado foi a artrodese póstero-lateral com instrumentação e descompressão associada. Os pacientes foram avaliados por VAS, índice de Oswestry e Roland-Morris no pré-operatório, com um mês, seis meses, um ano e dois anos de seguimento. Os dados foram analisados estatisticamente com nível de significância de 5%. RESULTADOS: O nível mais frequentemente operado foi L4-L5, com 52,38%. A VAS teve melhora significativa de 53,48% nos 6 meses após o procedimento. O Índice de Incapacidade de Oswestry apresentou piora no primeiro mês, evolução para melhora da capacidade até o sexto mês, e permaneceu constante até o fim do acompanhamento. Segundo o questionário de Incapacidade de Roland-Morris, houve melhora progressiva significativa até o sexto mês e, por último, uma leve piora. CONCLUSÃO: Os pacientes com espondilolistese degenerativa submetidos à artrodese póstero-lateral instrumentada e descompressão apresentaram melhora significativa da qualidade de vida e da dor após dois anos de acompanhamento.

Percutaneous pedicle screw reduction and axial presacral lumbar interbody fusion for treatment of lumbosacral spondylolisthesis: A case series

INTRODUCTION

Traditional surgical management of lumbosacral spondylolisthesis is technically challenging and is associated with significant complications. The advent of minimally invasive surgical techniques offers patients treatment alternatives with lower operative morbidity risk. The combination of percutaneous pedicle screw reduction and an axial presacral approach for lumbosacral discectomy and fusion offers an alternative procedure for the surgical management of low-grade lumbosacral spondylolisthesis.

CASE PRESENTATION

Three patients who had L5-S1 grade 2 spondylolisthesis and who presented with axial pain and lumbar radiculopathy were treated with a minimally invasive surgical technique. The patients-a 51-year-old woman and two men (ages 46 and 50)-were Caucasian. Under fluoroscopic guidance, spondylolisthesis was reduced with a percutaneous pedicle screw system, resulting in interspace distraction. Then, an axial presacral approach with the AxiaLIF System (TranS1, Inc., Wilmington, NC, USA) was used to perform the discectomy and anterior fixation. Once the axial rod was engaged in the L5 vertebral body, further distraction of the spinal interspace was made possible by partially loosening the pedicle screw caps, advancing the AxiaLIF rod to its final position in the vertebrae, and retightening the screw caps. The operative time ranged from 173 to 323 minutes, and blood loss was minimal (50 mL). Indirect foraminal decompression and adequate fixation were achieved in all cases. All patients were ambulatory after surgery and reported relief from pain and resolution of radicular symptoms. No perioperative complications were reported, and patients were discharged in two to three days. Fusion was demonstrated radiographically in all patients at one-year follow-up.

CONCLUSIONS

Percutaneous pedicle screw reduction combined with axial presacral lumbar interbody fusion offers a promising and minimally invasive alternative for the management of lumbosacral spondylolisthesis.

An evidence-based clinical guideline for the diagnosis and treatment of degenerative lumbar spondylolisthesis

BACKGROUND CONTEXT

The objective of the North American Spine Society (NASS) evidence-based clinical guideline on the diagnosis and treatment of degenerative lumbar spondylolisthesis is to provide evidence-based recommendations on key clinical questions concerning the diagnosis and treatment of degenerative lumbar spondylolisthesis. The guideline is intended to address these questions based on the highest quality clinical literature available on this subject as of January 2007. The goal of the guideline recommendations is to assist the practitioner in delivering optimum, efficacious treatment of and functional recovery from this common disorder.

PURPOSE

To provide an evidence-based, educational tool to assist spine care providers in improving the quality and efficiency of care delivered to patients with degenerative lumbar spondylolisthesis.

STUDY DESIGN

Systematic review and evidence-based clinical guideline.

METHODS

This report is from the Degenerative Lumbar Spondylolisthesis Work Group of the NASS Evidence-Based Clinical Guideline Development Committee. The work group was comprised of multidisciplinary spine care specialists, all of whom were trained in the principles of evidence-based analysis. Each member participated in the development of a series of clinical questions to be addressed by the group. The final questions agreed on by the group are the subject of this report. A literature search addressing each question and using a specific search protocol was performed on English language references found in MEDLINE, EMBASE (Drugs and Pharmacology) and four additional, evidence-based, databases. The relevant literature was then independently rated by at least three reviewers using the NASS-adopted standardized levels of evidence. An evidentiary table was created for each of the questions. Final grades of recommendation for the answer to each clinical question were arrived at via face-to-face meetings among members of the work group using standardized grades of recommendation. When Level I-IV evidence was insufficient to support a recommendation to answer a specific clinical question, expert consensus was arrived at by the work group through the modified nominal group technique and is clearly identified as such in the guideline.

RESULTS

Nineteen clinical questions were formulated, addressing issues of prognosis, diagnosis, and treatment of degenerative lumbar spondylolisthesis. The answers to these 19 clinical questions are summarized in this document. The respective recommendations were graded by the strength of the supporting literature that was stratified by levels of evidence.

CONCLUSIONS

A clinical guideline for degenerative lumbar spondylolisthesis has been created using the techniques of evidence-based medicine and using the best available evidence as a tool to aid practitioners involved with the care of this condition. The entire guideline document, including the evidentiary tables, suggestions for future research, and all references, is available electronically at the NASS Web site (www.spine.org) and will remain updated on a timely schedule.

Minimally invasive transforaminal lumbar interbody fusion with reduction of spondylolisthesis: technique and outcomes after a minimum of 2 years' follow-up

Minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) is a relatively new surgical procedure that appears to minimize iatrogenic soft tissue and muscle injury. The authors describe a technique for MI-TLIF that permits the surgeon to reduce spondylolisthesis percutaneously. The results in 40 consecutive patients who underwent MI-TLIF for symptomatic spondylolisthesis utilizing this approach are reviewed. Thirty cases involved a degenerative spondylolisthesis while the remaining 10 were isthmic. The minimum follow-up was 24 months with a mean of 35 months. The mean preoperative Oswestry Disability Index score was 55, decreasing to a mean of 16 postoperatively. The mean leg and back pain visual analog scale scores were 65 and 52, respectively, improving to means of 8 and 15. Reduction of the spondylolisthesis was achieved in all cases, with a mean decrease in forward translation of 76%. The authors conclude that MI-TLIF for symptomatic spondylolisthesis appears to be an effective surgical option with results that compare favorably to open procedures.

Soft stabilization with an artificial intervertebral ligament in grade I degenerative spondylolisthesis: comparison with instrumented posterior lumbar interbody fusion

BACKGROUND

The purpose of this retrospective study was to evaluate the efficacy of soft stabilization with an artificial intervertebral ligament after microdecompression for the treatment of grade I degenerative spondylolisthesis.

METHODS

From a total of 54 patients with degenerative spondylolisthesis who were treated surgically from May 2000 to April 2003, 36 patients who showed grade I spondylolisthesis without evidence of concomitant disc herniation necessitating discectomy were enrolled in the study. After decompression, the patients had undergone either soft stabilization with an artificial intervertebral ligament (n = 17) or instrumented posterior lumbar interbody fusion (PLIF; n = 19).

RESULTS

The average follow-up period was 24 months for the PLIF group and 16 months for the soft stabilization group. In the PLIF group, preoperative mean scores of 60% on the Oswestry Disability Index, 8.8 on the visual analog scale (VAS) for low-back pain, and 9.3 on the VAS for leg pain improved to 28%, 4.1, and 2.6, respectively, after surgery. Corresponding scores in the soft stabilization group were 55%, 8.4, and 8.9, improving to 25%, 4.1, and 2.2 after surgery. There were no significant differences between the 2 groups in any of these clinical parameters. Patients' subjective improvement rates and satisfaction with the surgical procedure were higher in the soft stabilization group, but the differences were not significant. Mean operation time and mean blood loss were significantly lower in the soft stabilization group than in the PLIF group. In the soft stabilization group, there were 3 cases of progression of slippage in patients who had had preoperative slippage of more than 20%; there was 1 dural tear in the PLIF group.

CONCLUSIONS

Patients with grade I degenerative spondylolisthesis who received soft stabilization with an artificial intervertebral ligament after microdecompression had clinical outcomes similar to those of patients who received PLIF. Since soft stabilization can be done in a much less invasive way than fusion, if slippage is 20% or less, soft stabilization with an artificial ligament is a viable alternative to fusion for patients who are elderly or who have significant comorbidities that make a prolonged operation inadvisable.

LEVEL OF EVIDENCE

This study was a retrospective comparative study with a very limited population (level III evidence).

Use of Recombinant Human Bone Morphogenetic Protein-2 as an Adjunct in Posterolateral Lumbar Spine Fusion

INTRODUCTION

This study determines whether recombinant human bone morphogenetic protein-2 (rhBMP-2) (12 mg at the rate of 1.5 mg/mL) delivered on an absorbable collagen sponge with an added bulking agent can increase posterolateral lumbar spine fusion success rates and decrease time for fusion with autogenous bone grafts.

METHOD

A prospective, single institution, clinical case-matched, radiographic, cohort study was undertaken. A total of 52 patients underwent posterolateral lumbar arthrodesis with pedicle screw instrumentation. The experimental group (n=41) underwent placement of Iliac crest bone graft (ICBG) with InFUSE (12 mg/level at the rate of 1.5 mg/mL). The control group (n=11) consisted of sex-matched patients, consecutively collected over the same time period with an instrumented posterolateral arthrodesis and ICBG placed in the intertransverse space.

OUTCOME MEASURES

Thin-cut (2 mm) axial, coronal, and sagittal reconstructions were blindly evaluated for evidence of bridging bone and cortication of the fusion mass by 3 separate reviewers. Fusions were graded and an overall score was given to the quality of the fusion mass.

RESULTS

Fifty patients (ICBG alone n=11; ICBG/rhBMP-2 n=39) were available for CT evaluation at 2-year follow-up. An overall 97% (68/70 levels; Definite+Probably Fused) fusion rate in the rhBMP-2 group was achieved as compared to the 77% fusion rate (17/22 levels) in the ICBG alone group (P<0.05). In the rhBMP-2 group, 92% of the patients (36/39 patients) received an overall excellent subjective fusion rating as compared to 27% (3/11) in the control group (P<0.05). There was no computed tomographic evidence of soft-tissue ossification, dural ossification, or laminar bone regrowth in any patient.

CONCLUSIONS

The adjunctive use of rhBMP-2 and ICBG seems to be safe and results in significantly larger and more consistent posterolateral fusion masses.

Treatment of instability and spondylolisthesis: surgical versus nonsurgical treatment

Spondylolisthesis is a common cause of lower-back pain, radiculopathy, and neurogenic claudication among the adult population. Treatment should begin with nonoperative measures that may include physical therapy, aerobic exercise, epidural steroid injections, and homeopathic remedies. If these treatments fail, surgical intervention may provide the patient pain relief and improvement in neurologic symptoms. The use of instrumentation for posterolateral fusions as well as interbody fusion may improve clinical outcomes for those having surgical intervention. We discuss the current nonoperative modalities and surgical techniques treating degenerative spondylolisthesis.

LEVEL OF EVIDENCE

Level V: Expert Opinion. See the Guidelines for Authors for a complete description of the levels of evidence.

Guidelines for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 9: fusion in patients with stenosis and spondylolisthesis

The best medical evidence available in the literature confirms the utility of fusion for improving patient outcomes following decompression for stenosis associated with spondylolisthesis. The majority of evidence from other studies comparing outcomes after decompression alone or decompression combined with PLF in patients with stenosis and spondylolisthesis also favors the performance of PLF. The medical evidence regarding the use of pedicle screw fixation in this patient population is rated as Class III and is inconsistent. A consistent benefit associated with the use of pedicle screw fixation has been reported in patients with preoperative instability or kyphosis. Iatrogenic instability following decompression is associated with poor outcomes and may also be treated with PLF involving supplemental instrumentation. The precise definition of instability or kyphosis has varied among researchers and requires further study.

Degenerative spondylolisthesis: review of current trends and controversies

STUDY DESIGN

A literature-based review.

OBJECTIVES

To review management and controversies and to present authors recommendations.

SUMMARY OF BACKGROUND DATA

There is considerable controversy regarding indication for surgery, role for decompression alone, and decompression with fusion with or without instrumentation.

METHODS

Review of English language medical literature.

RESULTS

The condition may stabilize itself with the collapse of the disc spaces and osteophytes but may continue to progress in nearly a third of the cases. It may cause predominantly back pain due to segmental instability, or radicular pain/neurogenic claudication secondary to root entrapment or spinal stenosis. When conservative treatment fails, the mainstay of surgical treatment is decompressive laminectomy and fusion, with or without instrumentation.

CONCLUSIONS

Decompression primarily relieves radicular symptoms and neurogenic claudication whereas fusion primarily relieves back pain by elimination of instability. The goals for instrumentation are to promote fusion and to correct deformity. Fusion has a better long-term outcome than decompression alone. There is evidence that instrumentation improves fusion rate but does not improve clinical outcome in a relatively short-term follow-up. However, outcome of pseudarthrosis cases deteriorates over time and solid fusion produces better long-term outcome. The benefit of instrumentation comes with a price of higher postoperative morbidity and complication rate. Bone morphogenetic proteins are being tried to increase the rate of fusion, without increasing the complication rate, but the cost is prohibitive. More recently, dynamic stabilization with instrumentation but without fusion has been introduced as an alternative treatment. The current trends of surgical treatment and controversies are discussed.

Posterior lumbar interbody fusion for degenerative spondylolisthesis: restoration of sagittal balance using insert-and-rotate interbody spacers

BACKGROUND CONTEXT

Although satisfactory clinical outcomes have been reported for degenerative spondylolisthesis using a variety of surgical techniques, its optimal management remains controversial. Laboratory and clinical evidence is emerging that if fusion surgery is undertaken, improved short- and longer-term outcomes may be achieved by correcting any sagittal deformity present. The insert-and-rotate posterior lumbar interbody fusion (PLIF) technique, first described by Jaslow in 1946, may enable surgeons to safely and effectively correct sagittal balance through a single posterior approach.

PURPOSE

To examine the clinical outcomes and determine whether the focal sagittal imbalance associated with a degenerative lumbar spondylolisthesis can be safely and effectively corrected using a posterior distraction/reduction technique and insert-and-rotate interbody fusion spacers.

STUDY DESIGN/SETTING

A prospective, single-cohort, observational study of the clinical outcomes and retrospective radiological review, in a series of 34 patients with degenerative spondylolisthesis, who underwent surgery between September 2000 and October 2002.

PATIENT SAMPLE

Mean age of 65.1 years (range, 35 to 82 years). Thirty-two of the 34 patients underwent surgery principally for the relief of radicular leg pain. The principal indication for the fusion was the prevention of anticipated postdecompression instability in 68% of the patients. Mean preoperative slip was 20.0% (range, 12% to 33%). Mean preoperative focal lordosis was 13.2 degrees.

OUTCOME MEASURES

Patients were administered pre- and postoperative clinical outcome surveys recording Visual Analogue Pain Score (VAS), Low Back Outcome Score (LBOS), Short Form (SF)-12 and patient satisfaction questionnaires. Pre- and postoperative measurements of the percentage slip and lumbar lordosis of the involved segments were available on 17 patients. Statistical analysis was done using a two tailed, paired t test. SURGICAL METHODS: Decompressive laminectomy was followed by reduction of the spondylolisthesis using intervertebral disc space distraction and pedicle screw instrumentation. The vertebral bodies were supported with bilateral intervertebral lordotic spacers, inserted on their sides and rotated 90 degrees before placing bone graft to either side of them, within the disc space.

RESULTS

Mean follow-up time was 21.2 months (range, 12-32 months). No patients were lost to follow-up. Mean preoperative measures of VAS and LBOS of 5.3+/-2.2 and 24.8+/-15.6, respectively, improved to 2.2+/-2.1 (p<.001) and 44.8+/-18.0 (p<.001) at last follow-up. Thirty-one of 34 patients (91%) considered their outcome to be good or excellent. Mean preoperative slip reduced from 20.2% to 1.7% (92% correction, p<.001). Mean focal lordosis increased from 13.1 to 16.1 degrees (26.0% increase, p=.01). There were no device-related procedural complications. Postoperatively, three patients developed an ileus and one a possible deep wound infection, which settled on antibiotics. One patient required extension of his fusion at 12 months for adjacent segment stenosis.

CONCLUSIONS

This series suggests that PLIF for degenerative spondylolisthesis using an insert-and-rotate technique can yield high levels of patient satisfaction with low levels of complications and substantial deformity correction using a posterior only approach. Longer-term outcome studies are required regarding the relevance of the restoration of spinal balance.

Factors affecting reduction in low-grade lumbosacral spondylolisthesis

OBJECT

Lumbosacral spondylolisthesis (LSS) is a common disorder that often requires a stabilization and fusion procedure. The aim of this study was to determine the early neuroimaging-detected results of instrumentation-assisted (in situ) fusion with no attempt at surgical reduction of the deformity in patients with low-grade LSS. The neuroimaging results were evaluated to determine the extent of reduction and its correlation with different parameters.

METHODS

Thirty patients with low-grade LSS underwent short-segment transpedicular screw fixation; surgical reduction was not attempted. All patients underwent plain anteroposterior and lateral lumbar radiography, flexion-extension lateral lumbar radiography, and computerized tomography and magnetic resonance imaging of the lumbar spine before and after surgery. Postoperative measurements were determined on the late (9 to 12-month) postoperative radiographs. The findings were recorded and grouped. Correlation analysis was performed among the radiological findings, body mass index, age, and sex. Paired-sample t-tests were performed for each paired group to determine statistically significant differences. There was no significant difference in extent of deformity reduction in patients with different lordotic angles, sagittal-plane rotation angles, and intervertebral disc heights. The extent of reduction was statistically significant at the L4-5 level (p < 0.05), in patients younger than 50 years of age (p < 0.05), and in those in whom the facet joint angle was increased (p < 0.05).

CONCLUSIONS

The authors found that in cases of low-grade LSS, short-segment posterior stabilization (in situ fusion and fixation) does not require surgical reduction and in fact is associated with a measurable reduction when used as the sole treatment.